Catawba Great Falls—Dearborn Recreation Diversions – hydraulic modelling

The present study conducted by Czech Technical University in Prague (CTU) created a 1:20 Froude scaled hydraulic model of the masterplan design created by S2O Design and Engineering (S2O) for the Duke Energy (DE) within the project Catawba Great Falls—Dearborn Recreation Diversions. This model accurately portrayed the proposed designs for both the Main and Bypass channels at a scale that has been shown to provide accurate visual and measured information with regards to flow velocities, depths, character and wave shape, and size. Than the modelling study is able to correctly assess the safety issues of recreational users of the both diversions. First analysis of both models demonstrated that the proposed S2O Masterplan layout did not meet the defined specifications for this project mainly at Bypass channel. There were numerous areas in which flows were found to be shallow, surging in location and depth. The proposed changes by S2O at Bypass channel were found to be the optimal design configuration within the bounds of the study. Only minor changes were needed at Main channel to keep meet the defined criteria. The hydraulic modelling study of the Dearborn Recreation Diversions shows clear evidence about the character and the safety of proposed solutions for wide range of flow conditions. The study also provide detailed structural data about the final geometry using laser scanning to prepeare final project plans following the outputs of modelling study.

The objectives of thehydraulic models created for this study were:

• Build 1:20 scaled hydraulic models of both the Main and Bypass channels that were constructed and calibrated to the accuracy necessary to accurately model the S2O proposed design layout.
• Assess the Masterplan with respect to the specifications created by S2O, including depths (in-flow as well as in eddies), flow velocities, ability for canoes and rafts to remain stationary at specific points in the channel, and the ability of the masterplan to create safe whitewater features including stable waves, eddies and stream trajectory; and exluding stoppers, surging and flow instabilities.
• Evaluate the performance of the both channels for range of flowrates derived from operational schemes of the hydropower plants and water surface elevations in the lake,
• Evaluate the rating curves of the inflow structures of both channels
• Evaluate the influence of the bedrock formation on the flow characteristics and to determine which bedrock formation could be preserve and which have to be removed during the construction process.
• create detailed digital models of terrain using laser scanning of both models.

in operation 03/2023